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begun to recover. Both Monitor Wells GW-N8 and GW-N9 show seasonal fluctuations in water <br />levels as a result of recharge from the ditch irrigation system. There is no evidence of any <br />discernible responses to precipitation events at these wells. There are no single aquifer <br />(overburden or Dakota coal) monitorwells completed in the northwest portion of the New Horizon <br />1 permit area. Consequently, MonitorWells GW-N8 and GW-N9 have been incorporated and used <br />in both the overburden and Dakota coal potentiometric surface maps (Maps 2.04.7-2 and 2.04.7-3). <br />Potentiometric Surfaces <br />Potentiometric surface maps for the overburden, Dakota coal and underburden aquifers are <br />presented in Maps 2.04.7-2 and 2.04.7-3, respectively. <br />Overburden. The potentiometric surface map of the overburden is presented on Map 2.04.7-2. <br />The water level contours were constructed based on the static water level measurements made <br />in September, 1987 from five overburden monitorwells and two multiple completion (overburden <br />and Dakota coal) monitor wells. It was necessary to include the two multiple completion monitor <br />wells (GW-N8 and GW-N9) in the overburden potentiometric map because they are the only monitor <br />wells located in the northwest portion of the permit area. The overburden generally has the <br />shallowest static water level of the bedrock aquifers that are monitored within the study area, so the <br />multiple completion monitorwells should be representative ofthe overburden aquiferwater levels. <br />Groundwaterintheoverburdenaquiferisgenerallyunconfiningtoonlyslightlyconfining. Theflow <br />in the overburden is generally from the northeast to the southwest and is topographically controlled. <br />Potentiometric contours indicate that there is discharge of ground water along Tuttle and Calamity <br />Draws. The ridge that separates the two draws is a ground waterdivide, causing the ground water <br />to flow from the ridge top toward both Tuttle and Calamity Draws. The primary recharge area is <br />from the northeast and from vertical leakage from the irrigation ditches and flood irrigation. The <br />average water level gradient in the overburden is .0342 fUft with a range between .0333 ftlft and <br />.0375 ft/ft. <br />Dakota Coal. The potentiometric surface map of the Dakota coal is presented on Map 2.04.7-3. <br />The waterievel contours were constructed based on the static waterlevel measurements collected <br />in September, 1987 from seven Dakota coal monitor wells and two multiple completion <br />• (REVISED6/28/01) 2.04.7-6 <br />